Vibration of Small Particles Could Trigger Aftershocks of Earthquakes

Earthquakes can create copycat events up to 1,000 kilometres away — and this mimicked impact could be the result of the vibration of small particles, according to new computer simulations of seismic activity in the Earth.

New Scientist reports that a team of researchers from the Second University of Naples in Italy has developed a computer model that analyses the way grains between tectonic plates influence friction forces felt at their boundaries. The team has shown that at certain frequencies, small particles between the plates can becomes ‘lathered’, moving around and decreasing friction, making slip — and an earthquake — more likely, even up to 1,000 kilometres away.

Interestingly, they found that the magnitude of the seismic waves emanating from one earthquake don’t have much effect on the likelihood of inducing another earthquake — it’s just the frequency. “Each fault will have its own acoustic resonance frequency,” Lucilla de Arcangelis, one of the researchers, tells New Scientist. “If a signal arrives at this frequency, the fault that without perturbation would be quiet will trigger an earthquake.” The research is published in Physical Review Letters. [Physical Review Letters via New Scientist]